In general, a cubic effect expressing three dimensions occurs due to disparity between two eyes, i.e., binocular disparity caused by two eyes spaced apart from each other by a distance of about 65 mm. Namely, when each of the left and right eyes of the human body sees two-dimensional images that are related to each other, these two images are transmitted to the brain via the retinas of the eyes, and the brain fuses the images together, to regenerate senses of depth and the presence of the original three-dimensionality of the imaged object, wherein such a capability is known as stereography.
Therefore, stereoscopic image display devices that display three-dimensional stereoscopic images on a two-dimensional screen using the above-mentioned principle have been suggested. Currently, such suggested stereoscopic image display devices may be divided into glasses type stereoscopic image display devices and non-glasses type stereoscopic image display devices. In general, glasses type stereoscopic image display devices include an image generation unit generating an image for the left eye and an image for the right eye, and a 3D filter layer changing the polarizing direction of the images for the left and right eyes generated in the image generation unit, wherein the images for the left and right eyes transmitting the 3D filter layer are respectively separated and transmitted through a left eye lens and a right eye lens so that three-dimensional images may be recognized in the brains of viewers.
The images generated in the image generation unit may proceed in various directions. For example, a portion of the image for the left eye may be transferred to a right eye region, or a portion of the image for the right eye may be transferred to a left eye region, to cause a cross-talk phenomenon in which the image for the left eye and the image for the right eye are seen in an overlapped state. If the cross-talk phenomenon occurs, viewers may see cloudy images and feel dizzy.
Accordingly, in order to minimize cross-talk regions, a method of arranging a color filter substrate and a 3D filter layer so that a black matrix formed on the color filter substrate may be placed at a boundary portion between a left eye region and a right eye region of the 3D filter layer have been suggested. However, since a substrate exists between the 3D filter layer and the black matrix formed on the color filter, optical path errors corresponding to the thickness of the substrate may be caused, and it may also be practically difficult to arrange the color filter so that the black matrix of the color filter may not be accurately placed at the boundary portion between the left eye region and the right eye region.
In the related art, to address such limitations, the width of the black matrix is extended so that optical path error and pattern adjusting errors may be offset by each other. In this case, however, the amount of shielded light may be increased, resulting in a decrease in the brightness of image display devices.
In the related art, black matrices are mainly produced by a photolithography method or a printing method. In the printing method, curable ink including a solvent, a monomer/oligomer having unsaturated double bonds, a pigment or dye, a photoinitiator, and an additive is printed to form a black matrix. The photolithography method has limitations such as large consumption of unnecessary materials, a relatively complicated processes, large line width variations according to the surface state of a base material caused by high spreadability of curable inks, and non-uniform pattern line heights caused by the formation of non-flat but concave or convex patterns as a result of a difference in solvent volatilization rates between central portions and edge portions of the patterns during drying. It is difficult to obtain a cross-talk preventing effect if line widths and line heights of patterns are not constant, as described above. Furthermore, since it is difficult to form patterns having high aspect ratios by using such curable ink compositions, fine lines not wider than 60 μm are formed to have low heights, and thus a sufficient light shielding effect may not be obtained.
Accordingly, it is required to develop stereoscopic image display devices capable of effectively reducing cross-talk while minimizing a drop in the brightness thereof.